Joaquin Castro walking towards the steps of the Capitol to join House freshmen for their official photo.

Joaquin Castro walking up the steps of the Capitol.

House freshmen congregate on the steps of the Capitol to take their official photo on Nov. 15. Joaquin Castro can be seen greeting fellow congressmen.

House freshmen congregate on the steps of the Capitol in order to take the freshmen photo.

Joaquin Castro makes his way down the Capitol steps after taking a photo with fellow House freshmen.

Joaquin Castro on the steps of the Capitol after the House freshmen posed for their official photo on Nov. 15.

Joaquin Castro chatting with a reporter on the steps of the Capitol.

Joaquin Castro giving an interview in front of the Capitol on Nov. 15.

WASHINGTON — San Antonio Rep. Joaquin Castro will be one of a few select members of Congress who will share a stage with President Barack Obama when he marks the 50th anniversary of Martin Luther King Jr.'s "I Have a Dream" speech.

Obama, the first African-American president, will deliver remarks Wednesday on the very steps of the Lincoln Memorial where King delivered his address in 1963 during he March on Washington.